package org.wltea.analyzer.core;

/**
 * IK 中文分词  版本 5.0
 * IK Analyzer release 5.0
 * 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * 源代码由林良益(linliangyi2005@gmail.com)提供
 * 版权声明 2012，乌龙茶工作室
 * provided by Linliangyi and copyright 2012 by Oolong studio
 * 
 */

/**
 * IK词元对象 
 */
public class Lexeme implements Comparable<Lexeme>{
    //lexemeType常量
    //未知
    public static final int TYPE_UNKNOWN = 0;
    //英文
    public static final int TYPE_ENGLISH = 1;
    //数字
    public static final int TYPE_ARABIC = 2;
    //英文数字混合
    public static final int TYPE_LETTER = 3;
    //中文词元
    public static final int TYPE_CNWORD = 4;
    //中文单字
    public static final int TYPE_CNCHAR = 64;
    //日韩文字
    public static final int TYPE_OTHER_CJK = 8;
    //中文数词
    public static final int TYPE_CNUM = 16;
    //中文量词
    public static final int TYPE_COUNT = 32;
    //中文数量词
    public static final int TYPE_CQUAN = 48;
    
    //词元的起始位移
    private int offset;
    //词元的相对起始位置
    private int begin;
    //词元的长度
    private int length;
    //词元文本
    private String lexemeText;
    //词元类型
    private int lexemeType;
    
    
    public Lexeme(int offset , int begin , int length , int lexemeType){
        this.offset = offset;
        this.begin = begin;
        if(length < 0){
            throw new IllegalArgumentException("length < 0");
        }
        this.length = length;
        this.lexemeType = lexemeType;
    }
    
    /*
     * 判断词元相等算法
     * 起始位置偏移、起始位置、终止位置相同
     * @see java.lang.Object#equals(Object o)
     */
    public boolean equals(Object o){
        if(o == null){
            return false;
        }
        
        if(this == o){
            return true;
        }
        
        if(o instanceof Lexeme){
            Lexeme other = (Lexeme)o;
            if(this.offset == other.getOffset()
                    && this.begin == other.getBegin()
                    && this.length == other.getLength()){
                return true;            
            }else{
                return false;
            }
        }else{        
            return false;
        }
    }
    
    /*
     * 词元哈希编码算法
     * @see java.lang.Object#hashCode()
     */
    public int hashCode(){
        int absBegin = getBeginPosition();
        int absEnd = getEndPosition();
        return  (absBegin * 37) + (absEnd * 31) + ((absBegin * absEnd) % getLength()) * 11;
    }
    
    /*
     * 词元在排序集合中的比较算法
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    public int compareTo(Lexeme other) {
        //起始位置优先
        if(this.begin < other.getBegin()){
            return -1;
        }else if(this.begin == other.getBegin()){
            //词元长度优先
            if(this.length > other.getLength()){
                return -1;
            }else if(this.length == other.getLength()){
                return 0;
            }else {//this.length < other.getLength()
                return 1;
            }
            
        }else{//this.begin > other.getBegin()
            return 1;
        }
    }
    
    public int getOffset() {
        return offset;
    }

    public void setOffset(int offset) {
        this.offset = offset;
    }

    public int getBegin() {
        return begin;
    }
    /**
     * 获取词元在文本中的起始位置
     */
    public int getBeginPosition(){
        return offset + begin;
    }

    public void setBegin(int begin) {
        this.begin = begin;
    }

    /**
     * 获取词元在文本中的结束位置
     */
    public int getEndPosition(){
        return offset + begin + length;
    }
    
    /**
     * 获取词元的字符长度
     */
    public int getLength(){
        return this.length;
    }    
    
    public void setLength(int length) {
        if(this.length < 0){
            throw new IllegalArgumentException("length < 0");
        }
        this.length = length;
    }
    
    /**
     * 获取词元的文本内容
     */
    public String getLexemeText() {
        if(lexemeText == null){
            return "";
        }
        return lexemeText;
    }

    public void setLexemeText(String lexemeText) {
        if(lexemeText == null){
            this.lexemeText = "";
            this.length = 0;
        }else{
            this.lexemeText = lexemeText;
            this.length = lexemeText.length();
        }
    }

    /**
     * 获取词元类型
     */
    public int getLexemeType() {
        return lexemeType;
    }
    
    /**
     * 获取词元类型标示字符串
     */
    public String getLexemeTypeString(){
        switch(lexemeType) {

        case TYPE_ENGLISH :
            return "ENGLISH";
            
        case TYPE_ARABIC :
            return "ARABIC";
            
        case TYPE_LETTER :
            return "LETTER";
            
        case TYPE_CNWORD : 
            return "CN_WORD";
            
        case TYPE_CNCHAR : 
            return "CN_CHAR";
            
        case TYPE_OTHER_CJK :
            return "OTHER_CJK";
            
        case TYPE_COUNT :
            return "COUNT";
            
        case TYPE_CNUM :
            return "TYPE_CNUM";
            
        case TYPE_CQUAN:    
            return "TYPE_CQUAN";
            
        default :
            return "UNKONW";
        }
    }
        

    public void setLexemeType(int lexemeType) {
        this.lexemeType = lexemeType;
    }
    
    /**
     * 合并两个相邻的词元
     * @param l lexeme
     * @param lexemeType lexemeType
     * @return boolean 词元是否成功合并
     */
    public boolean append(Lexeme l , int lexemeType){
        if(l != null && this.getEndPosition() == l.getBeginPosition()){
            this.length += l.getLength();
            this.lexemeType = lexemeType;
            return true;
        }else {
            return false;
        }
    }
    

    public String toString(){
        StringBuffer strbuf = new StringBuffer();
        strbuf.append(this.getBeginPosition()).append("-").append(this.getEndPosition());
        strbuf.append(" : ").append(this.lexemeText).append(" : \t");
        strbuf.append(this.getLexemeTypeString());
        return strbuf.toString();
    }
    

}
